The invention discloses a waterproof elastic sealing gasket for a segment joint of a shield tunnel. The waterproof elastic sealing gasket is characterized in that the waterproof elastic sealing gasketcomprises a silicon foam inner core and an ethylene-propylene-diene monomer (EPDM) rubber outer tire wrapping the silicon foam inner core. During using, two pieces of elastic sealing gaskets are pasted in waterproof inserting grooves in two adjacent segments in a mirror symmetry mode correspondingly, and the sealing gaskets are extruded after the segments are spliced, so that the silicon foam inner cores contracts and produce contact stress, thus EPDM rubber is mutually fitted and extruded, and a waterproof sealing function is achieved accordingly. Compared with a single-component EPDM through hole rubber sealing gasket commonly used in the existing engineering technology field, the waterproof sealing gasket with the additionally-arranged silicon foam inner core has the advantages of uniform contact stress, close fitting, long-term load maintaining ability, high elasticity recovery ability and the like, the stress relaxation phenomenon of the waterproof sealing gasket under the long-term pressure can be effectively reduced. The waterproof elastic sealing gasket has great value for long-term waterproof performance of the shield tunnel.